Modern farmers have learned from the lessons of agricultural history that leaving fields with no protective cover can and does lead to severe soil errosion, if certain climactic conditions occur. Consequently, many farmers of today have adapted "no till" or at least low tillage farming techniques, where surface coverage is disturbed as little as possible.
Subterranean sweep blades (generally relatively flat blades have a V-shaped configuration wherein the point of the V is pointed in the direction of travel of the blade) are sometimes utilized for this purpose, since such sweep blades traverse the soil below surface level and, therefore, do not substantially disturb the crop residue or stubble left on the surface except for the relatively narrow path of the shank of the blade.
Although sweep blades are useful in helping to destroy weeds, such blades effectively agitate or work only a relatively thin layer of soil beneath the surface. Such agitating or working is important to farming operations as the unpacked or loosened soil tends to absorb more water, so as to reduce rain runoff and soil erosion, while providing planted crops with additional moisture.
However, many types of soil are such that the working due to the sweep blades is not sufficiently deep to allow for proper water absorption. This is especially true in the "hard pan" type soils in portions of Wichita, Kansas and other midwestern states, where the soil is very hard packed and prevents substantial moisture absorption, especially during hard rains.
Conventionally, farmers have deep tilled the hard pan fields using cultivating techniques that also included working of substantially all of the surface soil of a field, thereby destroying field cover and leaving the field susceptible to wind erosion. Deep tillage tools typically have a blade or tooth that is relatively narrow and is drawn through the soil relatively deep as compared to most other cultivating methods. The tooth tends to "shatter" the hard soil thereby unpacking the soil and allowing better water absorption.
Consequently, it is deemed desirable to be able to obtain the benefits of weed destruction, while also unpacking, agitating or loosening the earth beneath the surface enough to absorb a substantial amount of moisture without destroying most of the field cover.
It is also noted that conventional farm machinery for the tilling of the soil typically mounts sweep blades and cultivating tools on separate field traversing frames. Thus, if a farmer wanted to both sweep cut roots and cultivate a field, such procedures would require at least two trips around the field: one using the sweep blades and the second using the cultivating tools. It would also be difficult for the farmer to precisely follow his previous paths such that the shanks of both the sweep blades and the cultivator tools followed the same path, hence a substantial portion of the surface of the field would be likely to be disturbed.
No present farm implement combines the sweep blade tools and the deep tillage tools as a combined system so as to cut weeds with the sweep blade and at the same time deeply penetrate and agitate the subsoil without disturbing relatively wide portions of surface, all at the same time. The present invention combines the two operations so that both can be accomplished in a single pass of the farming tractor, thereby saving fuel and time without significant soil disruption.